Sen. Mark Warner announced Monday in a Facebook post that he supports same-sex marriage, just the most recent of a string of senators to do so.

Warner, a former Virginia Democratic governor and first-term senator, is up for re-election to his seat in 2014.

“I support marriage equality because it is the fair and right thing to do. Like many Virginians and Americans, my views on gay marriage have evolved, and this is the inevitable extension of my efforts to promote equality and opportunity for everyone,” Warner wrote. “I was proud to be the first Virginia governor to extend anti-discrimination protections to LGBT state workers. In 2010, I supported an end to the military’s ‘don’t ask, don’t tell’ policy, and earlier this month I signed an amicus brief urging the repeal of DOMA. I believe we should continue working to expand equal rights and opportunities for all Americans.”

Virginia is very much a purple state — it went for Obama in two consecutive presidential cycles, but Republicans fill many of its major state offices. Still, public opinion is trending quickly toward supporting gay marriage.

And so are the opinions of D.C. lawmakers.

Earlier this month, Sen. Rob Portman, R-Ohio, became the first Republican Senator to support same-sex marriage, after disclosing that his son, Will, is gay. Will Portman, a junior at Yale, penned an op-ed for the school’s daily newspaper explaining his process of coming out and expressing pride for his father. He characterized his father’s shift in opinion as a willingness to “take a political risk in order to take a principled stand.”

Over the weekend, Democratic Sen. Claire McCaskill of Missouri also announced her support of same-sex marriage. McCaskill, of course, returned to Washington in 2013 after surviving one of the nation’s most contentious Senate races. Without the immediate pressure of re-election and bolstered by a strong tide of support, McCaskill may have felt freer to voice her change of heart on gay marriage.

She, like Portman, cited personal relationships as informing her decision.

“My views on this subject have changed over time, but as many of my gay and lesbian friends, colleagues and staff embrace long term committed relationships, I find myself unable to look them in the eye without honestly confronting this uncomfortable inequality,” McCaskill wrote in a Tumblr post.

“Supporting marriage equality for gay and lesbian couples is simply the right thing to do for our country, a country founded on the principals [sic] of liberty and equality.

Good people disagree with me. On the other hand, my children have a hard time understanding why this is even controversial. I think history will agree with my children.”

GOP operatives pointed out on Sunday that shortly before her re-election McCaskill’s spokesman told the Springfield, Mo., News-Leader that she opposes discrimination but believes that states should “take the lead in determining marriage equality.”